Passively Q-switched and mode-locking fiber laser based on Sb2S3 saturable absorber

Abstract

Stable mode-locking pulses were obtained in an erbium-doped fiber laser (EDFL) by using antimony sulfide (Sb2S3) as saturable absorber (SA). The Sb2S3-SA fabricated with the optical deposition method was connected to a ring cavity of EDFL for Q-switching and mode-locking, respectively. When the configuration of the fiber cavity is compact with a cavity length of 5 m, Q-switched pulses were generated with repetition frequency from 60.6 kHz to 69.9 kHz by tuning the pump power. Moreover, when additional single-mode fiber (SMF) was inserted into the cavity, self-started mode-locking with ps pulses was obtained. For further investigating the performance of the SA in mode-locking, an inline fiber polarizer was inserted into the compact cavity to achieve hybrid mode-locking operation generating pulses with pulse widths of fs and a fundamental frequency of 29.2 MHz with a signal-to-noise ratio (SNR) of 76 dB. The experimental results indicate that the Sb2S3 material has great application prospects in ultrafast optics due to its excellent optical properties.